TY - JOUR
T1 - Integrin engagement-induced inhibition of human myelopoiesis is mediated by proline-rich tyrosine kinase 2 gene products
AU - Dylla, Scott J.
AU - Deyle, David R.
AU - Theunissen, Koen
AU - Padurean, Adrian M.
AU - Verfaillie, Catherine M.
N1 - Funding Information:
This work was supported by grants from the National Institutes of Health (RO1 HL-49930 and RO1 DK-53673), Leukemia and Lymphoma Society of America (H6377-97), the Tulloch Family Foundation and the McKnight Foundation to C.M.V., and the Bone Marrow Transplant Research Fund and NCI-awarded Cancer Biology Training Grant (CA09138) to S.J.D. We thank Craig Eckfeldt, Valerie McCullar, Rob Sheaff, Mark Blackstad, Janet Peller, Brad Anderson, and members of the Stem Cell Lab for technical insight and assistance. Additional thanks to Ivan Dikic and Wen Xiong for contributing constructs critical to these studies.
PY - 2004/4
Y1 - 2004/4
N2 - Objective Hematopoietic progenitor proliferation and differentiation are inhibited by integrin engagement of fibronectin (FN). Focal adhesion kinases have been shown to mediate intracellular signaling from integrins, and we recently demonstrated that gene expression and pre-mRNA splicing of the focal adhesion kinase, PYK2, is abnormal in CD34+ cells from chronic myelogenous leukemia (CML) patients. Here we investigated whether PYK2 gene products mediate integrin signaling in hematopoietic stem and progenitor cells. Methods Cord blood CD34+ cells were retrovirally transduced with vectors encoding Pyk2H, Pyk2, or the dominant negative-acting, kinase-deficient, C-terminal PYK2 fragment, PRNK, and myeloid proliferation and differentiation was assessed using colony-forming cell (CFC), long-term culture-initiating cell (LTC-IC), and liquid culture assays. Results CD34+ cells overexpressing Pyk2H or Pyk2 generated 50% less colony-forming unit granulocyte/macrophage (CFU-GM) than eGFP-transduced controls. Although the number of CFC generated by PRNK-expressing cells was unchanged, LTC-IC were significantly reduced. Culture of CD34+ cells on FN significantly reduced the generation of mature myeloid cells vs those cultured on BSA-coated wells, and could be overcome by addition of SCF. As is observed when integrins are engaged, overexpression of either Pyk2H or Pyk2 decreased committed myeloid progenitor proliferation and differentiation; however, SCF could not override this inhibition. Finally, as is observed when integrins are not engaged, PRNK-mediated inhibition of endogenous Pyk2H resulted in integrin-nonresponsive proliferation and differentiation of myeloid precursors and accelerated differentiation of primitive hematopoietic progenitors. Conclusion These studies indicate that PYK2 gene products mediate integrin-induced signals that regulate myelopoiesis.
AB - Objective Hematopoietic progenitor proliferation and differentiation are inhibited by integrin engagement of fibronectin (FN). Focal adhesion kinases have been shown to mediate intracellular signaling from integrins, and we recently demonstrated that gene expression and pre-mRNA splicing of the focal adhesion kinase, PYK2, is abnormal in CD34+ cells from chronic myelogenous leukemia (CML) patients. Here we investigated whether PYK2 gene products mediate integrin signaling in hematopoietic stem and progenitor cells. Methods Cord blood CD34+ cells were retrovirally transduced with vectors encoding Pyk2H, Pyk2, or the dominant negative-acting, kinase-deficient, C-terminal PYK2 fragment, PRNK, and myeloid proliferation and differentiation was assessed using colony-forming cell (CFC), long-term culture-initiating cell (LTC-IC), and liquid culture assays. Results CD34+ cells overexpressing Pyk2H or Pyk2 generated 50% less colony-forming unit granulocyte/macrophage (CFU-GM) than eGFP-transduced controls. Although the number of CFC generated by PRNK-expressing cells was unchanged, LTC-IC were significantly reduced. Culture of CD34+ cells on FN significantly reduced the generation of mature myeloid cells vs those cultured on BSA-coated wells, and could be overcome by addition of SCF. As is observed when integrins are engaged, overexpression of either Pyk2H or Pyk2 decreased committed myeloid progenitor proliferation and differentiation; however, SCF could not override this inhibition. Finally, as is observed when integrins are not engaged, PRNK-mediated inhibition of endogenous Pyk2H resulted in integrin-nonresponsive proliferation and differentiation of myeloid precursors and accelerated differentiation of primitive hematopoietic progenitors. Conclusion These studies indicate that PYK2 gene products mediate integrin-induced signals that regulate myelopoiesis.
UR - http://www.scopus.com/inward/record.url?scp=1642587849&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=1642587849&partnerID=8YFLogxK
U2 - 10.1016/j.exphem.2004.01.001
DO - 10.1016/j.exphem.2004.01.001
M3 - Article
C2 - 15050747
AN - SCOPUS:1642587849
SN - 0301-472X
VL - 32
SP - 365
EP - 374
JO - Experimental Hematology
JF - Experimental Hematology
IS - 4
ER -